Sanofi recalls some pediatric pandemic vaccine doses

Dec 15, 2009 (CIDRAP News) – Sanofi has recalled four lots of its prefilled syringe pandemic vaccine for children ages 6 months through 35 months after its post-distribution monitoring found that antigen content dropped slightly below required levels, a problem that federal officials say isn't linked to any safety concerns.

The US Centers for Disease Control and Prevention (CDC) said today in a health alert network message to healthcare providers that Sanofi has stopped distributing 0.25-mL syringes of its pediatric pandemic vaccine, which will remove the only thimerosal-free option for children younger than 2.

Thimerosal is a vaccine preservative that guards against contamination in multiuse vials. It contains mercury, and though some believe it is linked to autism and other disorders, scientific data have not shown a connection. However, the preservative has been eliminated from some vaccines because some people are still concerned about it.

In a background statement today the CDC said the pandemic vaccine for children age 6 months and older is still available in multidose vials that contain thimerosal. Healthy children over age 2 can receive the live attenuated influenza vaccine that is available as a nasal spray in single units that do not contain thimerosal.

The four recalled lots contained 800,000 doses, were shipped in November and were distributed throughout the United States, the CDC said. The recall does not apply to Sanofi's pandemic vaccine packaged in 0.5-mL prefilled syringes for older children and adults or its multidose vials, because those two formulations still meet antigen content specifications.

Both the CDC and the Food and Drug Administration (FDA) agree that the small decrease in antigen content is unlikely to produce a clinically significant reduction in immune response among those who received the recalled doses, and there is no need to revaccinate those who were immunized with them. However, the CDC's recommendation still stands that all children younger than 10 who have received their first dose of any of the vaccine formulations receive a second dose a month later to ensure the best immune response.

Sanofi detected the problem during ongoing stability testing after the vaccine was shipped to providers, because sometimes vaccine potency can wane over time, the CDC said. The company first notified the CDC and FDA on Dec 7 that the potency in one batch had dropped below regulatory limits, then tests detected the same finding in three more lots, all of which were properly filled during manufacturing.

All of the affected lots passed prerelease testing for purity, potency, and safety, the CDC said.

Len Lavenda, a spokesman for Sanofi, told CIDRAP News that the company is still investigating the root cause of the antigen drop in the smaller vaccine dose. He said other vaccine formulations made with the same bulk vaccine used to make the 0.25-mL doses have not shown a similar drop.

An antigen drop after a vaccine is made can occur after vaccine production but is extremely rate, Lavenda said, adding that he can't remember the problem ever occurring before with a Sanofi vaccine.

A range of antigen is required in a vaccine, and the recalled vaccine fell 12% below the middle of the range and 6% below the lower number, he said.

Lavenda said the amount of vaccine that is subject to the recall reflects 1% of Sanofi's overall pandemic vaccine production.

Sanofi is the only manufacturer licensed to make the pandemic H1N1 vaccine in the United States. Its production facility is in Swiftwater, Penn. The US government ordered 75 million doses of pandemic vaccine from the company, about 30% of the 251 million doses that the US Department of Health and Human Services has ordered from five companies.

In early November Sanofi said it expected to fulfill its government order by the end of the year.